Reference Manual

PMAC 2 Software Reference

PMAC Program Command Specification 319

GOSUB

Function

Unconditional Jump With Return

Type

Motion program (PROG only)

Syntax

GOSUB{data}

where:

• {data} is a constant or expression representing the line label to jump to.

• {letter} (optional) is any letter character except N or O.

Remarks

This command causes the motion program execution to jump to the line label (N or O) of

the same motion program specified in {data}, with a jump back to the commands

immediately following the GOSUB upon encountering the next RETURN command.

If {data} is a constant, the path to the subroutine will have been linked before program

run time, so the jump is very quick. If {data} is a variable expression, it must be

evaluated at run time, and the appropriate label then searched for.

The search starts downward in the program to the end, then continues (if necessary) from

the top of the program down.

A variable GOSUB command permits the equivalent structure to the CASE statement

found in many high-level languages.

If the specified line label is not found, the GOSUB command will be ignored, and the

program will continue as if the command had not occurred.

The CALL command is similar, except that it can jump to another motion program.

Example

GOSUB300 jumps to N300 of this program, to jump back on RETURN.

GOSUB8743 jumps to N8743 of this program, to jump back on RETURN.

GOSUB(P17) jumps to the line label of this program whose number matches the current

value of P17, to jump back on RETURN.